1. Field of the Invention
The invention relates to telecommunications networks, and more particularly, to the optimization of congestion conditions within such networks.
2. History of the Prior Art
Telephone instruments and other communications devices located in the same geographic area are conventionally connected with one another by means of switching equipment referred to as an exchange. Communications between telephone/data instruments located in geographic areas separated from one another and connected to different exchanges communicate with one another by means of a complex interconnection of both local exchanges and trunk exchanges linked together into a telecommunications network. Networks may take the form of a grouping of interconnected network elements, such as local exchanges, trunking exchanges, mobile radio exchanges, long distance exchanges, and combinations thereof. At each network level, traffic from one network element, such as an exchange, to another can take various routes through different exchanges. In the design of telecommunication exchanges and the provision of communications circuits for the different routes therebetween, there is often a considerable period of time between the design of the routes and the number of required circuits in each route, based upon measured traffic requirements, and the installation of those circuits. Frequently, the traffic pattern within a network will change drastically between the time that the circuits and routes within the network are designed and their actual implementation, leaving the capacity and arrangement of the communication paths of the network out of date and inappropriate to its requirements. Further, even when the routes of a network are adequate when installed, rapid advances of information technology and explosive growth of circuit requirements between various points can quickly outdate the routing capacity of a network and result in inefficient utilization of available equipment. For example, the addition of one or two international hotels in a region of a network can drastically affect the availability of communication circuits and virtually paralyze the network due to the tremendous increase in the circuit requirements to those hotels. Similarly, the addition of a database communications service supplier or customers with toll-free 800 services, to a network may dramatically increase the requirement for circuits to a particular destination and seriously disturb other communications within the network in the region of that subscriber.
Efficient network traffic management of the communication facilities within a network requires that a sufficient number of circuits are available to handle the traffic requirements to each destination without exaggerated congestion on last-choice traffic routes. It also requires that the network congestion is as even as possible on all last-choice routes and that there not be any undue excess capacity within the circuits of the routes which are actually provided in order to insure efficient utilization of resources. In addition, the telephone administration which operates a network has a limited budget and must get as much efficiency as possible out of the existing resources in each network.
Traffic patterns within a network can vary over a period of weeks or months when, for example, new hotels or new customers providing database services are added to an exchange forming part of the network. Similarly, traffic patterns can vary over a period of days, for example, when an international sporting event lasting several days is held at a particular geographic area within the network. In addition, traffic patterns in a network commonly vary over 24 hours, since traffic increases during certain hours of the business day and decreases to virtually zero during certain hours of the night and early morning.
Traffic patterns within a network are strongly affected by defective devices such as, so-called, "killer trunks" which are faulty trunk circuits which appear to be available to carry traffic, but which accept the traffic only to terminate the call and again appear available to take more traffic. In addition, traffic within a network is affected by, so-called, "black spots" which are routes which are experiencing exaggerated congestion, i.e. , levels of congestion which are much higher than the average route congestion within the network. The worst of each of the conditions are also sometimes referred to as deficiency "tops" within a network.
In the past, traffic management within a communications network has included procedures for periodically surveying the traffic patterns within the network and changing the configuration of circuits and routes in order to more efficiently handle the traffic. In addition, more routes and circuits are added to a network in anticipation of high call densities to a particular location or a particular region and to local events within that region. Conventional network management systems are also capable of changing the relative distribution of traffic loads between selected routes within the network in order to more efficiently balance the current utilization of the network. However, conventional traffic network management systems and procedures have generally strived to increase the availability of circuits and routes within a network to handle individual traffic demands rather than to reconfigure by redimensioning the routes and circuits within the network at another higher grade of service so that the overall network efficiency is maximized.
Prior art network control systems generate network traffic statistics and execute network supervision functions which detect overloaded parts of the networks, defective device groups, and allow the adjustment of alarm limits within exchanges of the network to attempt to increase the efficiency of communication within the network. However, if congestion levels and disturbance levels within the network are too low, the network facilities become too expensive on a per call basis. If network congestion is too high, revenue is lost.
The method and system of the present invention strives to maintain an even level of congestion on the last-choice routes at each network level along with the maintenance of alarm limits within each portion of the network at average network levels in order to maximize highest circuit availability and optimize network economy and utilization of manpower. The present system also dynamically controls the network based upon live-traffic data to achieve the optimum use of existing routes within and between the exchanges of the network by continuously reducing the network deficiency tops within each portion of the network and attempting to achieve an even level of congestion throughout the network. The present system also redimensions the existing resource in real-time based upon live traffic data, and determines the maximum traffic which can be carried by the existing resources at a desired grade of service, i.e. , congestion level. The overflow traffic which has no chance to result in conversation is then limited as closed as possible to its origin by using network management protective functions.